Hi Corolla,
Firstly you dont need new clubs to progress !!
To be perfectly honest you dont need to upgrade anything right now. For you to improve is very simple - its called practice, and plenty of it.
You will be able to advance through to the Pro Tier very easily with what you have. So save your money till later on.
Once you have worked your way up into the Pro Tier and learnt a little about how this game works - then you might want to have a look at upgrading.
It is foolish to work your way up through the tiers as fast as possible. You need to have a good solid all round game, and that will take you some time to achieve - so dont be in any rush.
WARNING - DO NOT PLAY 9 HOLE ROUNDS all the time. That is the fastest way to get to the top. Even worse would be to play them on the easiest courses !! A good score on 9 holes is doubled to calculate your rating (based on 18 hole round) - so be warned.
There are heaps of players here who have achieved Master in a very short time - only to find all of a sudden, that their game actually isnt really up to it - and the fun goes out of it very quickly. Then the complaining starts ... OK??
So - get practicing, and good luck with it.
Cheers
Doug